Conversion of corn gluten into a solid article

ABSTRACT

Disclosed are fast-curing, inexpensive corn-gluten resin compositions, methods for making them, methods for forming them into solid articles. In some embodiments, the resin composition includes corn meal gluten and a non-toxic organic acid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase filing under 35 U.S.C. 371 ofInternational Patent Application No. PCT/US2011/044483, filed Jul. 19,2011, which claims the benefit of U.S. Provisional Application Ser. No.61/365,541, filed Jul. 19, 2010, entitled “Conversion of Corn GlutenMeal Into a Solid Article Through the Use of a Non-Toxic Additive,” eachof which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention generally relates to fast-curing, inexpensivecorn-gluten polymer compositions, methods for making them, methods forforming them into solid articles.

Decades ago, modern society embraced the use of plastics and othersynthetic resins to make items such as disposable utensils, plates, etc.Today, modern society has turned “green”, looking for environmentallyconscious choices for everything from disposable utensils to the cars wedrive. Biofuels are being developed to power those cars, and arebecoming increasingly popular with consumers. Similarly, biopolymers arebeing developed for uses that were previously exclusive to the plasticsindustry.

These types of biopolymers and resins are made from renewable resources,are biodegradable and have many eco-friendly attributes. Because ofthis, biopolymers and resins are becoming increasingly more importantand popular. However, they must ultimately be able to compete withexisting materials on the basis of both performance and cost.

SUMMARY OF THE INVENTION

Some embodiments of the invention provide a resin composition formolding formed articles comprising:

a resin component itself comprising by weight of the resin component:

-   -   about 70% to about 99% w/w corn meal gluten,    -   about 1% to about 18% organic acid, and    -   an optional solvent.

Some embodiments of the invention provide that the resin compositionfurther comprises a reinforcement/filler component, thereinforcement/filler component comprising up to about 40% by weight ofthe resin composition.

Some embodiments of the invention provide for a formed articlecomprising:

-   -   a resin composition:    -   a resin component itself comprising by weight of the resin        component:        -   about 70% to about 99% w/w corn meal gluten,        -   about 1% to about 18% organic acid, and        -   an optional solvent.

Some embodiments of the invention provide for a formed article furthercomprising a reinforcement/filler component, the reinforcement/fillercomponent comprising up to about 40% by weight of the resin composition.

Some embodiments of the invention provide a method for forming anarticle comprising:

filling a heated mold with a resin composition described herein;

applying pressure to the mold;

optionally releasing the pressure;

curing the resin composition within the mold to form the article withinthe mold.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a graph depicting the flexural strength data presented inTable 1.

FIG. 2 is a graph depicting the flexural strength data presented inTable 2.

FIG. 3 is a graph depicting the flexural modulus data presented in Table2.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to fast-curing, corn-glutenpolymer compositions, suitable for a fast moving production line,methods for making them, methods for forming them into solid,plastic-like objects, and the objects so formed.

“Corn Gluten Meal” as used herein is a byproduct of corn (maize)processing that has historically been used as an animal feed or ananimal feed additive. Corn gluten meal is a heterogeneous, unrefinedproduct comprising corn gluten as well as other byproducts of the wetmilling process, including but not limited to protein (e.g. glutelins,zein), fiber, starch, corn oil, minerals, and xanthophylls. As a naturalproduct, the precise chemical composition of Corn Gluten Meal may varyfrom crop to crop and batch to batch. Corn gluten meal is often referredto as “CGM”. Corn gluten meal has a relatively high protein content,usually from about 40% to about 60%.

“Corn Gluten” as referred to herein is a protein substance that remainswhen starch is removed from corn, particularly during the wet millingprocess. Corn gluten may comprise a mixture of proteins and othersubstances. We note for clarity that “corn gluten” is not “wheat gluten”and corn gluten does not affect those allergic to wheat gluten or thosesuffering from Celiac's disease as wheat gluten (often referred tosimply as gluten). In some contexts, “corn gluten” and “corn glutenmeal” are synonymous. As used herein, “corn gluten” is synonymous with“corn gluten meal.”

Reference to corn gluten meal herein is meant to convey the relativelyunrefined product. It is contemplated that further refinements of thecorn gluten meal may yield corn gluten, particular components of corngluten, corn zein, and other refined products. These products may alsobe useful in the preparation of formed articles and as plasticsubstitutes. In fact those of skill in the art will recognize that theuse of such materials has been discussed. The invention herein involvesthe use of significantly less expensive corn gluten meal.

As described herein, corn gluten meal can be made into a resin-likematerial that may be shaped and formed into articles traditionallyformed of plastics. For example, disposable (or more to the point,compostable or biodegradable) eating utensils can be made with thecompositions and techniques described herein.

As we know from cornbread, corn gluten meal by itself (or hydrated) doesnot readily exhibit cohesive properties like vital wheat gluten. In thecooking setting, some kind of binder is used to achieve the desiredcohesiveness, such as eggs or small amounts of wheat flour. In theindustrial setting, significant pressures and temperatures are usuallyrequired to soften corn gluten to achieve molecular-scaleinterpenetration among the individual protein molecules.

The corn gluten meal based compositions described herein can be moldedinto solid, plastic-like articles at low pressures, such as the pressuregenerated by the weight of a 10 cm×10 cm stainless steel plate or about820 g.

Some formulations described herein comprise corn gluten meal and arelatively small amount of non-toxic, organic acid (e.g. about 15% byweight or less). These formulations can be molded in a single step, intoa solid article without having to subject it to high shear forces orpressures. Accordingly, less energy-intensive processing methods, suchas vacuum forming or stamping may be used in forming the objects.

Suitable non-toxic organic acids will have cross-linking ability or willhave the ability to initiate crosslinking between other molecules in thematerial. Some acids behave more effectively as chemical crosslinkers(or as chemical-crosslinking agents), while others behave moreeffectively as plasticizers (e.g. long-chained, fatty acids). Those ofskill in the art will recognize long lists of candidate plasticizers(such as fatty acids, polyhydric alcohols, etc), that do not function aschemical crosslinkers. Those of skill in the art will also recognizecandidate crosslinkers (e.g. aldehydes) which are toxic and/orinappropriate for use with the relatively crude corn meal, as opposed tomore refined corn proteins such as zein. Although any suitable non-toxicorganic acid can be used, for manufacturing and cost concerns severalinexpensive organic acids are widely available and useful on anindustrial scale. Similarly, those of skill in the art will recognizecandidate crosslinkers many of which are expensive and typically used tofix biological tissues (e.g. genepin or carbodiimide) and/or areinappropriate for use with the relatively crude corn meal. Suitablenon-toxic and inexpensive organic acids include, but are not limited to,C₁-C₈alkyl substituted with 1-3 —OH groups and 1-3 —CO(OH) groups,C₁-C₆alkenyl substituted with 1-3 —CO(OH) groups). The C₁-C₈alkyl basedorganic acids (with one or more —CO(OH) groups include but are notlimited to lactic acid, citric acid propionic acid, succinic acid, malicacid, malonic acid, valeric acid, tartaric acid, gluconic acid, andcaproic acid. The C₁-C₆alkenyl based acids include one or more doublebond and include but are not limited to maleic acid, sorbic acid,angelic acid, tiglic acid. Some embodiments use C₃-C₆alkyl substitutedwith 1-3 —OH groups and 1-3 —CO(OH) groups. In still other embodiments,C₃ alkyl substituted with 1-3 —OH groups and 1-3 —CO(OH) groups areused. Some embodiments use C₃-C₆alkenyl substituted with 1-3 —CO(OH)groups). We believe that some heterocyclic acids could work as well andinclude but are not limited to uric acid, ascorbic acid, benzoic acid,and salicylic acid. There are also volatile acids that could be toxic athigh concentrations, such as acetic acid or oxalic acid, but couldpotentially promote crosslinking at low concentrations. It may also beuseful to use some of these acids in combination with each other (e.g.sorbic acid and lactic acid).

It has been discovered that, in particular, lactic acid, sorbic acid,and citric acid appear to be very promising. Two of these molecules haveat least one carboxylic acid group and one alcohol group and onemolecule has at least one carboxylic acid group and one double bond.Thus, we believe suitable non-toxic organic acids include those havingat least one carboxylic acid group and one alcohol group or at least onecarboxylic acid group and one double bond.

As described below, it has been discovered that some acids are moreeffective than others in their effect on flexural strength, an importantproperty in “plastic” articles. Importantly, it has been discovered thatunlike the acids mentioned above fatty acids do not appear to impart thedesired characteristics to the formed article. In fact, when 10% oleicacid was added, it actually reduced flexural strength compared to corngluten meal alone (the control). The non-toxic, organic acids can beadded in an amount of less than about 18% by weight of the composition.However, if these acids are added in excess (e.g. 25% or 30% citricacid), they can also reduce the flexural strength compared to corngluten meal alone. Above these levels, the excess acid can behave morelike a plasticizer, which is traditionally used at these higher levels(about 20% to about 30%). In some embodiments, the non-toxic organicacids can be present in an amount from about 0.5% to about 18% by weightof the composition. In some embodiments, the non-toxic organic acid ispresent below about 15% by weight of the composition. In someembodiments, the non-toxic organic acid is present below about 10% byweight of the composition. In some embodiments, the non-toxic organicacid is present at about 1% to about 10%. In some embodiments, thenon-toxic organic acid is present at about 5% to about 7.5% by weight ofthe composition.

Corn gluten meal can be in powder or pellet form or formed into a dough.Although the pelletized form may be used, in some instances, it is firstground into a powder for improved handling and function. When mixed witha suitable amount of a non-toxic, organic acid and placed in a heatedmold and compressed under nominal load, a solid article is formed.

Thermosetting reactions usually occur at low pressures, and typicallyinvolve the formation of covalent bonds. In thermoplastic processing,however, chemical bonds are not necessarily formed; typically, thepolymer chains entangle with each other under high heat and pressure,yielding a solid plastic article. Process aids are often added tofacilitate the formation of a polymer melt. However, if the process aidsare not correctly selected, the strength of the final part could beadversely affected. The correctly selected process aid also promotesretention of molded shape, and promotes durability while still allowingbiodegradation. Balance between short-term use and durability, andlonger-term biodegradability is critical.

The curable formulations disclosed herein are different from thesethermoplastic formulations described in the scientific literature in thefollowing ways:

Much lower quantities (10% or less) of certain additives is all that isneeded in the mixture to achieve a fast-curing, “vacuum-formable”, corngluten meal based plastic. This is clearly a delicate process, as anumber of parameters appear to be important, such as solubility, numberof functional groups (e.g. carboxylic acid groups, alcohol groups,double bonds, etc.), polarity, etc. In certain cases, the additive couldserve multiple functions; e.g. as both a process aid and a curing agent,or as both a curing agent and a preservative, or as a process aid,curing agent, and a preservative.

In accordance with some embodiments of the invention, a resincomposition is made from corn meal gluten and a non-toxic organic acid.In some embodiments, the resin composition comprises:

-   -   a resin component comprising:    -   about 70% to about 99% corn meal gluten by weight of the resin        component;    -   about 1% to about 18% non-toxic organic acid; and    -   an optional solvent.

The solvent may be water or other benign solvent such as but not limitedto propylene glycol, glycerol, etc. The addition of solvent aids increating a flowable resin that may be poured into a mold.

In some embodiments, the ratio of corn meal gluten to non-toxic organicacid is about 99:1; about 98:2; about 97:3; about 95:5; about 92.5:7.5;about 90:10; and about 87.5:12.5; and range between any of those.

One or more environmentally-friendly reinforcement or filler materialsmay optionally be used in the compositions and methods described herein.Such reinforcement or filler materials include but are not limited tonatural fibers, sawdust, inorganic fibers, foaming agents, clays,zeolites, and combinations thereof.) Such optional fillers arecontemplated as high as 30 to 40% w/w of the composition, based upondesired conditions such manufacturing concerns, wetness, strength,interfacial properties between polymer and the filler, etc. In someembodiments the reinforcement or filler materials are added to the resincomponent at a ratio of up to about 40% reinforcement/filler material to60% resin component by weight of the total resin composition. In someembodiments, the ratio of reinforcement/filler material to resincomponent is about 30:70; about 25:75; about 10:90, and ranges betweenany two of these.

To form a desired article, the starting materials are mixed, in theamounts described above, having about 70% to about 99% corn gluten mealand about 1% to about 18% non-toxic organic acid, as described above.Water and/or another benign solvent (e.g. propylene glycol, glycerol,etc.) may be added to aid in mixing and to create a viscous, pourableliquid, which aids in filling the forms.

Once mixed, an appropriate amount is placed in a heated mold. A balancemust be achieved employing adequate heat in order to promotecrosslinking, but not so much heat that the material thermallydecomposes. Typically this is about 180° F. to about 350° F., but can beadjusted based on the components used and conditions. An initial load ofnominal pressure (e.g. approximately 3-5 MPa) is applied to compress thestarting material, which minimizes voids within the mold. The appliedload may then be released and the material allowed to cure within theheated mold for about 20 minutes, bearing the weight of just the topcover plate (e.g. 0.084 MPa). The mold is allowed to cool to roomtemperature, and the articles are then removed. The load applied and thecure time will vary depending upon the exact formulation used, the sizeof the mold, the size of the molded article, the number of moldedarticles, etc. Alternatively, the material may be processed underapplied loads (e.g. approximately 4-5 MPa for 10 minutes) to facilitatemixing and the formation of both chain entanglements and crosslinks inthe material.

Any type of molded article may be produced in a similar manner. It isparticularly contemplated that the formulations and methods describedherein are well suited to the production of disposable (compostable,biodegradable) eating and/or serving utensils. For that matter, plates,serving dishes, containers, clamshells or any other formed article maybe made via similar techniques.

It is also contemplated that the corn gluten meal formulations describedherein, could be used as a degradable binder for application of certainfiller materials. For example the corn gluten meal formulation could bemade to bind insulative fibers into a form for ease of installation.Once installed, the corn gluten meal formulation would degrade, leavingbehind only the insulative materials.

Those of skill in the art will readily recognize that other additivescan also be used. For example, one or more preservatives, colorants,texturizers, etc. can be used depending upon the desired application.One of skill in the art will readily recognize that additional additivescan be employed to alter odor, appearance, shelf-life, degradationcharacteristics, durability, cost, etc.

EXPERIMENTAL PROTOCOL AND EXAMPLES

Material Preparation (Series 1)

Corn gluten meal is available in both pellet form and powder form. Inthis particular series of experiments, pellets were used. The pelletswere ground to a fine powder in order to achieve a more uniform blend.

Example 1

Control: 65 g corn gluten meal (97% corn gluten meal, 3% molasses pelletbinder; purchased from Uhler's, Malvern, Pa.) were placed in a 10 cm×10cm stainless steel mold.

Example 2

180 g of citric acid were dissolved in 20 mL de-ionized water and heatedfor 40 sec in a microwave. The contents were then poured into a foodprocessor mixing chamber, along with 100 g ground corn gluten meal andpulse-mixed for 1 min (The food processor is equipped with a metalblade.) The mixture was poured into a glass beaker and heated again for45 sec, and afterwards was mixed with another 80 g of ground corn glutenmeal. The citric acid-modified corn gluten meal was kept in pellet formand stored in a sealed bag in the freezer until use. This procedureyielded a 50:50 (w/w) citric acid/corn gluten meal composition.

Example 3

Mixed 16.25 g of the citric acid-modified corn gluten meal blendprepared in Example 2 with 48.75 g corn gluten meal, yielding a materialcomprising approximately 87.5% corn gluten meal and 12.5% (w/w) citricacid.

Example 4

Mixed 13 g of the citric acid-modified corn gluten meal blend preparedin Example 2 with 52 g corn gluten meal, yielding a material comprisingapproximately 90% (w/w) corn gluten meal and 10% (w/w) citric acid.

Example 5

Mixed 9.75 g of the citric acid-modified corn gluten meal blend preparedin Example 2 with 55.25 g corn gluten meal, yielding a materialcomprising approximately 92.5% (w/w) corn gluten meal and 7.5% (w/w)citric acid.

Example 6

Mixed 6.5 g of the citric acid-modified corn gluten meal blend preparedin Example 2 with 58.5 g corn gluten meal, yielding a materialcomprising approximately 95% (w/w) corn gluten meal and 5% (w/w) citricacid.

Example 7

Mixed 6.5 g lactic acid with 58.5 g corn gluten meal, yielding amaterial comprising approximately 90% (w/w) corn gluten meal and 10%(w/w) lactic acid.

Example 8

Mixed 6.5 g lactic acid with 58.5 g corn gluten meal, yielding amaterial comprising approximately 90% (w/w) corn gluten meal and 10%(w/w) lactic acid.

Example 9

Mixed 6.5 g oleic acid with 58.5 g corn gluten meal, yielding a materialcomprising approximately 90% (w/w) corn gluten meal and 10% (w/w) oleicacid.

Example 10

Mixed 3.25 g lactic acid with 61.75 g corn gluten meal, yielding amaterial comprising approximately 95% (w/w) corn gluten meal and 5%(w/w) lactic acid.

Example 11

Mixed 4.87 g lactic acid with 60.13 g corn gluten meal, yielding amaterial comprising approximately 92.5% (w/w) corn gluten meal and 7.5%(w/w) lactic acid.

Example 12

Mixed 6.5 g palmitic acid with 58.5 g corn gluten meal, yielding amaterial comprising approximately 90% (w/w) corn gluten meal and 10%(w/w) palmitic acid.

Example 13

Mixed 6.5 g sorbic acid with 58.5 g corn gluten meal, yielding amaterial comprising approximately 90% (w/w) corn gluten meal and 10%(w/w) sorbic acid.

Example 14

Mixed 6.5 g maleic acid with 58.5 g corn gluten meal, yielding amaterial comprising approximately 90% (w/w) corn gluten meal and 10%(w/w) maleic acid.

Example 15

Mixed 6.5 g malic acid with 58.5 g corn gluten meal, yielding a materialcomprising approximately 90% (w/w) corn gluten meal and 10% (w/w) malicacid.

Example 16

Mixed 1.95 g lactic acid with 63.05 g corn gluten meal, yielding amaterial comprising approximately 97% (w/w) corn gluten meal and 3%(w/w) lactic acid.

Example 17

Mixed 1.3 g lactic acid with 63.7 g corn gluten meal, yielding amaterial comprising approximately 98% (w/w) corn gluten meal and 2%(w/w) lactic acid.

Example 18

Mixed 0.65 g lactic acid with 64.35 g corn gluten meal, yielding amaterial comprising approximately 99% (w/w) corn gluten meal and 1%(w/w) lactic acid.

Specimen Preparation (Series 1):

All plaques were compression molded using a Carver press (Carver, model#3851-0). The starting material was placed in a stainless steel mold (10cm×10 cm×0.4 cm). The mold was placed in the press. (The temperature ofthe platens was set at 290 F.) An initial load of approximately 3 to 5MPa was applied in order to compress the starting material and minimizevoids within the mold. The applied load was then released and thematerial was allowed to cure within the heated mold for 20 minutes,bearing the weight of just the top cover plate (0.084 MPa). In thisseries of experiments, the application of load was kept lowintentionally in order to avoid masking the effect of the organic acid.The plaques were demolded after the mold had cooled down to roomtemperature. All of the plaques in this series of experiments weremolded within the same 10-day period.

Mechanical Testing: Flexural Strength (Series 1)

Plaques were cut into test specimens using a table saw to strips of1.1-1.5 cm in width and 9.5-10.0 cm in length. The test specimens wereconditioned at 70% humidity and 70° F. for 24 hours prior to testing.Flexural tests were conducted using an Instron model 1125 in accordancewith modified ASTM D790 flexural test. The gauge length was set at 62 mmand the crosshead speed was 10 mm/min.

Table 1 below shows average flexural strength in the exemplary samplesof series 1. FIG. 1 is a graphical representation of the data.

TABLE 1 Average Flexural Standard Sample Formulation Strength (MPa)Deviation (MPa) size (n) corn gluten control 4.576 2.98 30 1% (w/w)lactic acid 6.610 1.14 4 2% (w/w) lactic acid 9.522 2.16 6 3% (w/w)lactic acid 9.549 1.86 6 5% (w/w) lactic acid 11.79 2.42 11 7.5% (w/w)lactic acid 8.972 2.05 6 10% (w/w) lactic acid 6.044 1.52 6 5% (w/w)citric acid 7.920 1.38 6 7.5% (w/w) citric acid 5.816 1.49 5 10% (w/w)citric acid 9.550 1.76 5 25% (w/w) citric acid 2.310 1.11 27 30% (w/w)citric acid 2.344 0.980 4 10% (w/w) malic acid 7.177 0.771 6 10% (w/w)maleic acid 7.925 0.877 10 10% (w/w) oleic acid 2.942 1.712 6 10% (w/w)palmitic acid 4.982 0.467 4 10% (w/w) sorbic acid 12.34 1.49 6

As described above, and evident from the above table, each acidinteracts with corn gluten meal proteins differently, and in contrast toprior art teachings, organic acids do not appear to be readilyinterchangeable.

Corn gluten specimens that contained lactic acid [1-7.5% w/w] and sorbicacid [10% w/w] appeared to out-perform all the others in terms offlexural strength. Without being bound by the theory, the inventorsbelieve this may be due to the effect of these acids in promoting theformation of chemical bonds in the material. That is, these acids appearto aid in the forming of chemical crosslinking bonds.

Specimens containing 10% or less organic acid (lactic acid, citric acid,malic acid, maleic acid, or sorbic acid) clearly out-performed specimenscontaining fatty acid (oleic acid or palmitic acid): flexural strengthsof the specimens containing 10% fatty acid were all below average, whilethe flexural strengths of the specimens containing 10% or less organicacid being at least average or above average

Applicants believe, as noted by at least one observer, (Padua et al.),that long fatty acid chains form physical bonds with the protein chains,not chemical bonds. These physical bonds are not chemical cross-linkingbonds believed to be present in the organic acid based formulations.Similarly excess (citric) acid (25% or 30% w/w citric acid) appears tobehave more like a plasticizer than a crosslinker, which may be why thespecimens containing excess organic acid (25% or 30% w/w citric acid)performed well below the grand average of modified and unmodifiedspecimens.

Specimens containing 5% (w/w) lactic acid and 10% (w/w) sorbic acidyielded highest strengths on average.

Average flexural strength of unmodified corn gluten meal specimens waswell below the grand average (4.58 MPa) of modified and unmodifiedspecimens, thus indicating that the addition of non-toxic organic acidat about 10% or less had significant effect on the flexural strength ofthe product formed through heat with nominal pressure.

Material Preparation (Series 2)

Example 19

Control: 65.00 g corn gluten meal (97% corn gluten meal, 3% molassespellet binder; purchased from Uhler's, Malvern, Pa.) were placed in a 10cm×10 cm stainless steel mold.

Example 20

Mixed 1.30 g succinic acid with 63.70 g corn gluten meal, yielding amaterial comprising approximately 98% (w/w) corn gluten meal and 2.0%(w/w) succinic acid.

Example 21

Mixed 3.25 g sorbic acid with 62.75 g corn gluten meal, yielding amaterial comprising approximately 98% (w/w) corn gluten meal and 4.9%(w/w) sorbic acid.

Example 22

Mixed 1.30 g maleic acid with 63.70 g corn gluten meal, yielding amaterial comprising approximately 98% (w/w) corn gluten meal and 2.0%(w/w) maleic acid.

Example 23

Mixed 1.30 g sorbic acid with 63.70 g corn gluten meal, yielding amaterial comprising approximately 98% (w/w) corn gluten meal and 2.0%(w/w) sorbic acid.

Example 24

Mixed 3.25 g succinic acid with 62.75 g corn gluten meal, yielding amaterial comprising approximately 98% (w/w) corn gluten meal and 4.9%(w/w) succinic acid.

Specimen Preparation (Series 2):

All plaques were compression molded using a Carver press (Carver, model#3851-0). The starting material was placed in a stainless steel mold (10cm×10 cm×0.4 cm). The mold was placed in the press. (The temperature ofthe platens was set at 290 F.) A load of approximately 4 to 5 MPa wasapplied to the material for 10 minutes. The plaques were demolded afterthe mold had cooled down to room temperature. All of the plaques in thisseries of experiments were molded within the same 4-day period.

Mechanical Testing: Flexural Strength (Series 2)

Plaques were cut into test specimens using a table saw to strips of1.1-1.5 cm in width and 9.5-10.0 cm in length. The test specimens wereconditioned at 70% humidity and 70° F. for 24 hours prior to testing.Flexural tests were conducted using an Instron model 1125 in accordancewith modified ASTM D790 flexural test. The gauge length was set at 62 mmand the crosshead speed was 10 mm/min

TABLE 2 Average Avg Sam- Aver- Flexural Standard Flexural Standard pleage Strength Deviation Modulus Deviation size Den- Formulation (MPa)(MPa) (GPa) (GPa) (n) sity corn gluten 11.78 2.06 0.914 0.345 7 1.25control 2.0% (w/w) 11.26 1.58 1.06 0.219 8 1.25 succinic acid 2.0% (w/w)11.97 0.978 1.41 0.108 13 1.26 maleic acid 2.0% (w/w) 14.00 1.21 1.540.122 7 1.26 sorbic acid 4.9% (w/w) 13.38 1.49 1.29 0.222 7 1.25succinic acid 4.9% (w/w) 16.56 1.58 1.70 0.0938 7 1.26 sorbic acid

Specimens containing 5% (w/w) sorbic acid yielded highest strengths andmodulii on average in both sets of experiments (Series 1 & 2). Thehigher strength and modulus of the specimens containing sorbic acidsuggests that the crosslinking was enhanced by the sorbic acid. Swellingtests were also conducted to investigate material crosslinking Two 10cm×10 cm plaques prepared according to Examples 19 and 24 (corn glutencontrol and 4.9% (w/w) sorbic acid-modified corn gluten). The plaqueswere then immersed in water for 20 h at room temperature. After 20 h inwater, the weight of the corn gluten control specimen had increased by48.0%, and was accompanied by visible cracking, while the weight of the4.9% (w/w) sorbic acid-modified corn gluten specimen had increased byonly 35.8% and no cracking was evidenced. This result further suggeststhat the presence of sorbic acid in the material enhances crosslinking,and the absence of cracking suggests an enhanced toughness.

The description herein is meant to be illustrative of the invention andis not intended to limit the invention. Those of skill in the art willreadily recognize variants and applications of the experiment that arewithin the scope and spirit of the description herein and are deemed tobe part of the invention disclosed herein.

What is claimed is:
 1. A resin composition for molding formed articleswith crosslinked corn meal gluten, the composition comprising: a resincomponent itself consisting of: about 87.5% to about 99% w/w corn mealgluten, about 1% to about 12.5% non-toxic, crosslinking organic acid,and an optional solvent.
 2. The resin composition of claim 1 furthercomprising a reinforcement filler component, the reinforcement fillercomponent comprising up to about 40% by weight of the resin composition.3. The composition of claim 1, wherein the organic acid is selected fromlactic acid, citric acid, sorbic acid, malic acid, succinic acid, andmaleic acid.
 4. The resin composition of claim 1, wherein the corn mealgluten resin component comprises at least about 98% corn meal gluten byweight of the resin component.
 5. The resin composition of claim 1,wherein the corn meal gluten resin component comprises at least about97% corn meal gluten by weight of the resin component.
 6. The resincomposition of claim 1, wherein the corn meal gluten resin componentcomprises at least about 92.5% corn meal gluten by weight of the resincomponent.
 7. The resin composition of claim 1, wherein the corn mealgluten resin component comprises at least about 90% corn meal gluten byweight of the resin component.
 8. The composition of claim 2, whereinsaid reinforcement filler component is selected from natural fibers,sawdust, inorganic fibers, inorganic particles, foaming agents, clays,zeolites, and combinations thereof.
 9. A fast-cured, crosslinked cornmeal gluten article formed at low pressures from a resin compositioncomprising: a resin component itself consisting of: about 87.5% to about99% w/w chemically crosslinked corn meal gluten, and about 1% to about12.5% non-toxic chemical crosslinker wherein the chemical crosslinker isan organic acid wherein the article is formed within about 20 minutes attemperatures between about 180 F to about 350 F and under pressuresbetween about 3 to about 5 MPa.
 10. The formed article of claim 9,further comprising a reinforcement filler component, the reinforcementfiller component comprising up to about 40% by weight of the resincomposition.
 11. The formed article of claim 9, wherein the organic acidis selected from lactic acid, citric acid, sorbic acid, malic acid,succinic acid, and maleic acid.
 12. The formed article of claim 9,wherein the corn meal gluten resin component comprises at least about98% corn meal gluten by weight of the resin component.
 13. The formedarticle of claim 9, comprising wherein the resin component comprises atleast about 97% corn meal gluten by weight of the resin component. 14.The formed article of claim 9, comprising wherein the resin componentcomprises at least about 92.5% corn meal gluten by weight of the resincomponent.
 15. The formed article of claim 9, comprising wherein theresin component comprises at least about 90% corn meal gluten by weightof the resin component.
 16. The formed article of claim 10, wherein saidreinforcement filler component is selected from natural fibers, sawdust,inorganic fibers, inorganic particles, foaming agents, clays, zeolites,and combinations thereof.
 17. A method for forming a fast-cured articlewith chemically crosslinked corn meal gluten comprising the steps of:filling a mold heated to between about 180 F to about 350 F with a resincomposition according to claim 1; applying pressure to the mold betweenabout 3 to about 5 MPa; and curing the resin composition within the moldfor about 10 to about 20 minutes to form the article with chemicallycrosslinked corn meal gluten within the mold.
 18. A fast-cured,crosslinked corn gluten polymer article formed in a heated mold from aresin composition consisting essentially of corn gluten, wherein thecorn gluten is crosslinked in the mold forming the article at atemperature between about 180 F to about 350 F and under a pressuresufficient to minimize voids within the mold.
 19. The formed article ofclaim 18, wherein the article is formed under a pressure between about 3to about 5 MPa.
 20. The formed article of claim 18 further comprising areinforcement filler component.
 21. The formed article of claim 20,wherein the reinforcement filler component comprises up to about 40% byweight of the resin composition.
 22. The formed article of claim 20,wherein the ratio of reinforcement filler material to corn gluten in theresin composition is about 30:70.
 23. The formed article of claim 20,wherein the ratio of reinforcement filler material to corn gluten in theresin composition is about 25:75.
 24. The formed article of claim 20,wherein the ratio of reinforcement filler material to corn gluten in theresin composition is about 10:90.
 25. The formed article of claim 20,wherein said reinforcement filler component is selected from naturalfibers, sawdust, inorganic fibers, inorganic particles, foaming agents,clays, zeolites, and combinations thereof.
 26. A method for forming afast-cured cross-linked article with corn gluten comprising the stepsof: filling a mold heated to between about 180 F to about 350 F with aresin composition consisting essentially of corn gluten; applying apressure to the mold sufficient to minimize voids within the mold; andcrosslinking the corn gluten within the mold to form the article. 27.The method of claim 26, wherein the article is formed under a pressurebetween about 3 to about 5 MPa.